Once common in the rocky intertidal, these marine mollusks have been affected by overfishing and disease. Thanks to research and conservation, these grazers are making a comeback!

Size frequency on islands

Figure App.F.13.2.. A figure showing the sizes of black abalone across the Channel Islands from th 1985 - 2014.

Figure App.F.13.2.. A figure showing the sizes of black abalone across the Channel Islands from th 1985 - 2014.

Click for Details Box plots for annual size frequency distributions of black abalone Haliotis cracherodii at each island. Blue lines represent mean sizes of H. cracherodii at each island pooled across and sites. Red lines represent the cumulative mean. Figure: Channel Islands National Park

Density & counts on islands

Figure App.F.13.1. A figure showing the density of of black abalone across the Channel Islands from 1985 - 2014 in fixed plots in the rocky intertidal. The inset figure shows actual counts from site-wide searches (1995 - 2014).

Figure App.F.13.1. A figure showing the density of of black abalone across the Channel Islands from 1985 - 2014 in fixed plots in the rocky intertidal. The inset figure shows actual counts from site-wide searches (1995 - 2014).

Click for Details Black abalone Haliotis cracherodii mean density from fixed plots from 1985–2014 (left) and mean counts from site-wide searches from 1995–2014 (inset) at four islands in Channel Islands National Marine Sanctuary. Site wide search counts began in 1995 due to the severe declines in abundance that occurred from 1985–1995. Generally, increasing abundances began approximately in the 2007–2009 timeframe. Error bars were constructed using one standard error from the mean. Figure: Channel Islands National Park